1. Chapter 1 Lecture The Science of Nutrition Third Edition © 2014 Pearson Education, Inc. The Science of Nutrition: Linking Food, Function, and Health

2. © 2014 Pearson Education, Inc. What Is Nutrition? Food is the plants and animals we eat Nutrition is the science that studies food: –How food nourishes our bodies –How food influences our health –Includes identifying how we consume, digest, metabolize, and store nutrients –Includes studying our eating patterns and making recommendations

3. © 2014 Pearson Education, Inc. Why Is Nutrition Important? Proper nutrition supports wellness –Wellness is more than the absence of disease –Includes physical, emotional, and spiritual health –Is a multidimensional, lifelong process Two key components of wellness that we examine: 1. Nutrition 2. Physical activity

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5. Why is Nutrition Important? Can improve health and prevent disease One of several factors supporting wellness Can prevent some diseases and reduce risk for others

6. © 2014 Pearson Education, Inc. Why is Nutrition Important? Relationship between poor nutrition and disease: –Poor nutrition causes deficiency diseases such as scurvy and pellagra –Plays a role in the development of osteoporosis and cancer –Is associated with chronic diseases including heart disease, stroke, and type 2 diabetes –Direct link with rapid rise in obesity over past 25 years

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10. Why is Nutrition Important? Nutrition is part of the U.S. national health promotion and disease prevention plan: Healthy People (updated every 10 years)

11. © 2014 Pearson Education, Inc. Healthy People 2020 Four primary goals: –Help people attain higher quality and longer lives, via prevention of disease, disability, injury, and premature death –Achieve health equity; improve health for all –Create social and physical environments that promote health –Promote quality of life, healthy development, and healthy behaviors across all life stages

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13. What Are Nutrients? Nutrients are chemical substances critical for human growth and function, found in foods –Organic nutrients contain carbon and hydrogen, essential components of all living organisms; they include carbohydrates, lipids, proteins, vitamins –Inorganic nutrients are those not containing carbon and hydrogen; they include minerals and water

14. © 2014 Pearson Education, Inc. What Are Nutrients? Six groups of nutrients found in foods: Organic: –Carbohydrates –Lipids (fats and oils) –Proteins –Vitamins Inorganic: –Minerals –Water

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16. What Are Nutrients? Macronutrients are required in relatively large amounts –Provide energy/fuel to our bodies –Carbohydrates, lipids, and proteins Alcohol = not a nutrient –Does not support regulation of body functions or the building or repairing of tissues –Considered to be both a drug and a toxin

17. © 2014 Pearson Education, Inc. Carbohydrates Primary fuel source for the body, especially for neurologic functioning and physical exercise Composed of chains of carbon, hydrogen, and oxygen Found in grains (wheat, rice), vegetables, fruits, legumes (lentils, beans, peas), seeds, nuts, and milk products

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19. Lipids A diverse group of substances that are largely insoluble in water Includes triglycerides, phospholipids, and sterols Composed of carbon, hydrogen, and oxygen Main energy source during rest or low- to moderate-intensity exercise Stored as adipose tissue (body fat) Provide fat-soluble vitamins

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21. Proteins In addition to carbon and hydrogen, proteins also contain nitrogen Not typically a primary energy source; important in building new cells/tissues, maintaining bone, repairing damage, and regulating metabolism and fluid balance Found in many foods, particularly meat, dairy, seeds, nuts, and legumes; small amounts in grains and vegetables

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23. Micronutrients: Vitamins Organic compounds that assist in regulating body processes: –Build and maintain healthy bones and tissues –Support immune system –Ensure healthy vision –Do not contain or supply energy to our bodies –Help us utilize the energy derived from macronutrients –Can be destroyed by light, heat, air, etc. Two types: fat-soluble and water-soluble

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25. Micronutrients: Minerals Inorganic substances required for body processes: –Regulate fluid and energy production –Support bone and blood health –Remove harmful metabolic by-products –Exist in the simplest possible form; can't be broken down further or destroyed by heat/light Two types: major and trace minerals

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27. Micronutrient: Water A vital inorganic nutrient supporting all body processes: –Fluid balance –Energy production –Regulation of nerve impulses, body temperature, and muscle contractions –Nutrient transport –Excretion of waste products Sources include water in its pure form, juices, other drinks, and many foods.

28. © 2014 Pearson Education, Inc. Determining Nutrient Needs Dietary Reference Intakes (DRIs): updated nutritional standards –Expanded on the previous RDA values –Set standards for nutrients that do not have RDA values –Dietary standards for healthy people only –Aim to prevent deficiency diseases and reduce chronic diseases

29. © 2014 Pearson Education, Inc. Determining Nutrient Needs Dietary Reference Intakes (DRIs) consist of: 1.Estimated Average Requirement (EAR) 2.Recommended Dietary Allowance (RDA) 3.Adequate Intake (AI) 4.Tolerable Upper Intake Level (UL)

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31. Determining Nutrient Needs Estimated Average Requirement (EAR) –The average daily intake level of a nutrient to meet the needs of half of the healthy people in a particular life stage or gender group –Used to define the Recommended Dietary Allowance (RDA) of a nutrient

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33. Determining Nutrient Needs Recommended Dietary Allowance (RDA) –The average daily nutrient intake level that meets the needs of 97% to 98% of healthy people in a particular life stage and gender group

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35. Determining Nutrient Needs Adequate Intake (AI) –Recommended average daily nutrient intake level –Based on observed and experimentally determined estimates of nutrient intake by a group of healthy people –Used when the RDA is not available: calcium, vitamin D, vitamin K, and fluoride

36. © 2014 Pearson Education, Inc. Determining Nutrient Needs Tolerable Upper Intake Level (UL) –Highest average daily nutrient intake level likely to pose no risk of adverse health effects to most people –Consumption of a nutrient at levels above the UL increases the potential for toxic effects and health risks increases

37. © 2014 Pearson Education, Inc. Determining Nutrient Needs Estimated Energy Requirement (EER) –Average dietary energy intake to maintain energy balance in a healthy adult –Defined by age, gender, weight, height, and level of physical activity

38. © 2014 Pearson Education, Inc. Determining Nutrient Needs Acceptable Macronutrient Distribution Ranges (AMDR) –Ranges of energy intakes from macronutrients that are associated with reduced risk of chronic disease while providing adequate intakes of essential nutrients –If nutrient intake falls outside this range, there is a potential for increasing our risk for poor health

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40. Assessing Nutritional Status Nutrition professional must have a thorough understanding of a client's current nutritional status –Weight –Ratio of lean body tissue to body fat –Intake of energy and nutrients Foundation of recommended dietary and lifestyle changes Baseline for evaluation

41. © 2014 Pearson Education, Inc. Malnutrition Nutritional status is out of balance: too much or too little of a particular nutrient or energy over a significant period of time Undernutrition: too little energy or too few nutrients over time, causing weight loss or a nutrient-deficiency disease Overnutrition: too much energy or too much of a given nutrient over time, causing obesity, heart disease, or nutrient toxicity

42. © 2014 Pearson Education, Inc. Physical Examinations Should be conducted by trained healthcare providers Tests depend on client's medical history, disease symptoms, and risk factors Typical tests include vital signs, lab tests, heart and lung sounds Nutritional imbalances may be detected by examining hair, skin, tongue, eyes, and fingernails

43. © 2014 Pearson Education, Inc. Health History Questionnaire Tool for cataloging history of health, illness, drug use, exercise, and diet Can be used to assess energy and nutrient intakes Information includes: –Age, height, weight, medications (present & past) –Family heath/disease history, exercise history –Socioeconomic factors (race/ethnic background, education level, marital status, etc.)

44. © 2014 Pearson Education, Inc. Other Dietary Intake Tools Additional techniques to assess nutrient and energy intakes: –Diet history –Twenty-four-hour dietary recall –Food frequency questionnaire –Diet records

45. © 2014 Pearson Education, Inc. Anthropometric Assessments Provide objective data Common measurements include height, body weight, head circumference in infants, and limb circumference Require trained personnel and correct tools Compare standards specific for age/gender Assess trends in nutritional status/growth

46. © 2014 Pearson Education, Inc. Nutrition Deficiencies Primary deficiency occurs when a person does not consume enough of a nutrient, a direct consequence of inadequate intake Secondary deficiency occurs when: –A person cannot absorb enough of a nutrient in his or her body –Too much of a nutrient is excreted from the body –A nutrient is not utilized efficiently by the body

47. © 2014 Pearson Education, Inc. Deficiency Symptoms Subclinical deficiency occurs in the early stages; few or no symptoms are observed Covert symptoms are hidden and require laboratory tests or other invasive procedures to detect Symptoms of nutrition deficiency that become obvious are overt

48. © 2014 Pearson Education, Inc. Scientific Method To ensure that certain standards and processes are used in evaluating claims, the researcher: 1.Makes an observation and describes a phenomenon 2.Proposes a hypothesis (educated guess) to explain the phenomenon 3.Develops an experimental design to test the hypothesis 4.Collects and analyzes data to support or reject the hypothesis

49. © 2014 Pearson Education, Inc. Scientific Method If the data are rejected, an alternative hypothesis is proposed and tested If the data support the original hypothesis, a conclusion is drawn The experiment must be repeatable, so other researchers can obtain similar results

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51. Well-Designed Experiment The sample size (number of people being studied) should be adequate to ensure that the results obtained are not due to chance alone A control group is essential for comparison between treated and untreated individuals Control for other variables is applied to avoid coincidentally influencing the results

52. © 2014 Pearson Education, Inc. Advancing a Theory A hypothesis that is consistently supported by repeated experiments becomes a theory A theory represents a scientific consensus (agreement) of why a phenomenon occurs Theories can be challenged and changed as scientific knowledge evolves

53. © 2014 Pearson Education, Inc. Types of Research Studies Human studies: –Difficult to control for all of the variables –Humans have long life spans Animal studies –Preliminary information for designing and implementing human studies –Research that cannot be done with humans –Drawbacks: results may not apply directly to humans; ethical implications of animal studies

54. © 2014 Pearson Education, Inc. Types of Research Studies Observational studies: –Involve assessing nutritional habits, disease trends, or other health phenomena of large populations –Determine the factors that may influence these phenomena

55. © 2014 Pearson Education, Inc. Types of Research Studies Case control studies are more complex observational studies with additional design features –Compare a group of individuals with a particular condition to a similar group without the condition Clinical trials are tightly controlled experiments –Experimental group receives an intervention/treatment –Control group is not given an intervention/treatment

56. © 2014 Pearson Education, Inc. Other Aspects of Research Studies Key aspects in evaluating clinical trials: –Randomized trials: Researchers randomly assign participants to the treatment and control groups; reduces the possibility of favoritism and errors –Single-blind experiments: Participants are not aware of which (if any) treatment is being given –Double-blind experiments: Both the participants and the researchers are not aware of which group is getting a treatment

57. © 2014 Pearson Education, Inc. Evaluating Media Reports Conflict of interest –Key questions to ask: Who/what group conducted the study? Who paid for it? Was the study funded by a company or corporation that stands to profit from the results? Did the researchers receive good, services, money, or perks from the research sponsor? Do the researchers have investments or ties to companies or products related to the study?

58. © 2014 Pearson Education, Inc. Evaluating Media Reports Website reliability; separating internet fact from fiction –Check credentials of website sponsors and/or information suppliers Qualified professionals? Are financial contributors' names available? Is there expert review of content? –Check website date Is it current? Is information subject to change over time? Should it be consistently updated? –Check sources of information (for-profit or not?) Look for ".gov"/".edu"/".org" as reliable designations

59. © 2014 Pearson Education, Inc. Evaluating Media Reports More ways to discern truth from fiction: –Who is reporting the information? –Is the report based on reputable research studies? –Is the report based on testimonials? –Are the claims too good to be true? Quackery: promotion of an unproven product or service -- usually by an unlicensed or untrained source -- for financial gain

60. © 2014 Pearson Education, Inc. Trustworthy Nutrition Experts Reliable experts have education and credentials, such as: –Registered dietician (RD) –Licensed dietician: meets state credentialing requirements –Professional with an advanced, related degree: master's or doctorate degree (MA, MS, PhD) –Medical doctor/physician "Nutritionist" has no legal definition or laws regulating it

61. © 2014 Pearson Education, Inc. Government Information Sources Government-affiliated online sources (".gov") are considered reliable, such as: –Centers for Disease Control and Prevention (CDC) –National Health and Nutrition Examination Survey (NHANES) –Behavioral Risk Factor Surveillance System (BRFSS) –National Institutes for Health (NIH)

62. © 2014 Pearson Education, Inc. Reliable Professional Organizations American Dietetic Association American Society for Nutrition Sciences Society for Nutrition Education American College of Sports Medicine North American Association for the Study of Obesity